Question

Law of cosines: a2 = b2 + c2 – 2bccos(A)

Which equation correctly uses the law of cosines to solve for y?

92 = y2 + 192 – 2(y)(19)cos(41°)
y2 = 92 + 192 – 2(y)(19)cos(41°)
92 = y2 + 192 – 2(9)(19)cos(41°)
y2 = 92 + 192 – 2(9)(19)cos(41°)

Answer 1

In other words, the answer on edu is D

Explanation:

The guy on top explains it well tho, credit to him

Answer 2

The answer to your question is: y2 = 92 + 192 – 2(9)(19)cos(41°) . The last option.

Explanation:

In the picture, we notice that

a = y

b = 9

c = 19

A = 41

then, we substitute in the formula given

y² = 9² + 19² - 2(9)(19)cos (41)

and we can solve it

y² = 81 + 361 - 258.11

y² = 442 - 258.11

y² = 183.89

y = 13.6 u